The cause of all this devastation being visited upon Ely was John's idea of revenging himself upon the barons. At their hands he had, the year previously, been compelled to undergo the mortification of signing the Magna Charta at Runnymede, a field between Windsor and Staines. Ever since that time the irresolute and mean king had been devising schemes of vengeance against his opponents. Three months spent in the Isle of Wight had enabled him, through agents and the promise of the estates of the barons as plunder, to raise a considerable army of the Brabanters. At their head he suddenly emerged from concealment, and surprised the barons by appearing before Rochester Castle and defeating them. In the meantime John was well supported at Ely by his general, William Bunk, or rather an unexpected incident hurried on its doom. The elements unkindly betrayed the city into the hands of the Brabanters. At a critical time, the treacherous swamps--the isle's hitherto great natural fortifications--became the city's undoing; for a sharp frost set in and rendered a ready glacial access to the city. The enemy lost no time in reducing the barons to submission and the wretched inhabitants to great misery. The barons, thus reduced to dire extremities, invited Louis, the eldest son of the King of France, to aid them, promising him through his wife the crown of England. [Illustration: ELY INTERIOR OF THE NAVE] The French landed at Sandwich, retook Rochester Castle, and compelled John to flee. John, crossing over the Wash, in his march from Lynn in Norfolk into Lincolnshire, suffered great loss through the return of the tide swamping the rear of his army, all his money, and stores. He himself escaped to Swineshead Abbey, in the Lincolnshire Fens, where a monk is said to have administered poison to him. With great difficulty and exhaustion the monarch arrived at Newark, where he died in the October of the year 1216. From this time onward the city enjoyed comparative peace, and exercised the privileges granted by Edgar, Edward the Confessor, and William the Conqueror. Till the twenty-seventh year of the reign of Henry VIII. the royal franchise of Ely, in several statutes, was recognised as the county palatine of Ely. Henry, by Act of Parliament, remodelled the privileges, and ordered the justices of oyer and terminer, and gaol delivery, and justices of the peace for the Isle of Ely, to be appointed by letters patent under the Great Seal. The dissolution of the monasteries also was the means of converting the conventual church into a cathedral--much more appropriate to the dignity of the Bishop, whose title had been granted, as we have seen, by Henry I. in 1107. This ecclesiastical building, first a conventual and then a cathedral church, was commenced in 1081, and entirely completed in 1534. The dedication to St. Peter and St. Ethelreda was changed to "The Holy Trinity."